Historically, the most common bolt action rimfire receivers use rear lock-up: the locking lugs are associated with the bolt handle and lock into the rear of the receiver. This design allows the receiver to be free from lug ways propagating through the receiver and terminating at the breech of the barrel. The rear lock-up manufacturing approach is easier and more economical than conventional methods for manufacturing a mid lock-up receiver, but the design produces a less accurate rifle than one with a mid lock-up receiver.
A less common, but more desired design, are mid lock-up receivers: the locking lugs on the bolt are located midway through the receiver. Forward of the bolt body is a bolt nose that remains stationary to the turning of the bolt body. Although the mid lock-up arrangement is preferred for rifle accuracy, it has generally been avoided because the design is more difficult and costly to manufacture. In addition, available manufacturing processes dictate the lug ways run the full length of the receiver without terminating at the abutments. This produces a less rigid receiver and minimal support for the bolt nose, which adversely affect rifle accuracy.
Prior art examples of mid lock-up receivers are the Remington 40X 22LR, Kelbly Swindlehurst, and Stiller Lonestar. It should be appreciated that only the Stiller Lonestar remains in production. Production of these receivers was short-lived because of their high manufacturing cost. In the case of the Kelbly and Stiller receivers, potential customers balked at purchasing them because of their perceived accuracy disadvantage resulting from them having lug ways continuing forward of the abutments.
Therefore, a need exists for a new and improved mid lock-up receiver that can be manufactured economically without lug ways that continue forward of the abutments. In this regard, the various embodiments of the present invention substantially fulfill at least some of these needs. In this respect, the mid lock-up receiver according to the present invention substantially departs from the conventional concepts and designs of the prior art, and in doing so provides an apparatus primarily developed for the purpose of providing a mid lock-up receiver that can be manufactured economically without lug ways that continue forward of the abutments.